Analysis of spectral response in P-type GaAs/GaInP QWIPs

1995 ◽  
Vol 18 (4) ◽  
pp. 249 ◽  
Author(s):  
J. Hoff ◽  
C. Jelen ◽  
S. Slivken ◽  
E. Bigan ◽  
M. Razeghi ◽  
...  
Keyword(s):  
Spectral Response ◽  
P Type

Chemical Vapor Deposited Graphene for Opto-Electronic Applications

2016 ◽  
Vol 39 ◽  
pp. 57-68
Author(s):  
Vikram Passi ◽  
Amit Gahoi ◽  
Sarah Riazimehr ◽  
Stefan Wagner ◽  
Andreas Bablich ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Spectral Response ◽  
Single Layer ◽  
Chemical Vapor ◽  
Adsorbed Water ◽  
Single Layer Graphene ◽  
Ambient Conditions ◽  
Transfer Length ◽  
Type Silicon ◽  
P Type

In this work, fabrication and characterisation of graphene photodiodes and transfer length method structures is presented. Graphene growth is carried out using a thermal chemical vapor deposition process on copper foils and subsequently transferred onto silicon-dioxide/silicon substrate. Comparison of electrical and optical characteristics of the photodiodes, which are fabricated on both n-type and p-type silicon, is shown. The photodiodes fabricated on n-type silicon show good rectifying behaviour when compared with photodiodes fabricated on p-type silicon. Spectral response of graphene photodiodes is measured to be less than 0.2 mAW-1 which is attributed to the light absorbance of 2.3% for single layer graphene. Transfer length method device structures are also fabricated and contact resistance is calculated and plotted as a function of spacing between the contacts. The calculated contact resistance (RcW) is 0.87 kΩ.µm. The latter structures are also characterised under various ambient conditions, before and after annealing. The value of contact resistance reduces from 0.87 kΩ.µm to 0.75 kΩ.µm after annealing. This reduction is attributed to the improvement in bonding between graphene and metal. Measurements under vacuum show an increase in contact resistance which is attributed to the removal of adsorbed water molecules on the surface on graphene. The sheet resistivity of graphene is calculated to be between 1.17 kΩ/□ and 3.67 kΩ/□.

Preparation and Characterisation of (ZnTe)x(CdSe)1−x Single Crystals

1989 ◽  
Vol 161 ◽  
Author(s):  
V.K. Madhu Smitha Rani ◽  
R.P. Vijayalakshmi ◽  
D. Raja Reddy ◽  
B.K. Reddy
Keyword(s):  
Chemical Analysis ◽  
Single Crystals ◽  
Entire Range ◽  
Energy Gap ◽  
Spectral Response ◽  
Alloy System ◽  
Crystalline Form ◽  
Reflection Spectra ◽  
Alloy Material ◽  
P Type

ABSTRACTThe titlematerial is one of the least studied among the II-VI alloy systems. So far it has not been possible to prepare ZnTe in n-type and CdSe in p-type with appreciable conductivities. Moreover ZnTe crystallises in zincblende whereas CdSe crystallises in wurtzite structure. Because of the varied nature of the end compounds, an attempt has been made to prepare single crystals of (ZnTe)x(CdSe)1−x in the entire range of ‘x’. The alloy material in the entire range Xof composition in the single crystalline form was grown by a modified Piper-Plich method. The grown crystals of this alloy system have been subjected to chemical analysis. DTA and DTG studies carried out on these alloys did not show any phasec transitions. However two exothermic peaks associated with increase in mass were noticed. This has been attributed to oxidation effects of Se/Te or Cd/Zn. XRD data though showed some regularity near end compositions there is still some ambiguity for the middle compositions. Energy gap obtained from reflection spectra and also photocurrent spectral response showed bowing. However, there is a marked different feature at one of the end regions. The growth and the results of all the above mentioned investigations are presented and discussed in this paper.

Effect of the Hetero-Interface on the Photoresponse of A-Si/C-Si Solar Cells

1994 ◽  
Vol 358 ◽  
Author(s):  
B. Jagannathan ◽  
J. Yi ◽  
R. Wallace ◽  
W. A. Anderson
Keyword(s):  
Solar Cells ◽  
Crystalline Silicon ◽  
Spectral Response ◽  
Forward Bias ◽  
Depletion Region ◽  
Defect States ◽  
Heterojunction Solar Cells ◽  
Si Solar Cells ◽  
Wavelength Absorption ◽  
P Type

ABSTRACTHeterojunction solar cells were fabricated by glow discharge deposition of amorphous silicon on p-type crystalline silicon resulting in a n/i/p structure. Dark I-V-T data on the devices show that the conduction in the forward bias regime (<0.4 volts) for better devices agrees with a multi-tunnelling-capture-emission process. The photoresponse was evaluated (under 100 mW/cm2) for various a-Si thicknesses and substrate resistivities. Spectral response tests showed an increased low wavelength absorption as the a-Si thickness was decreased. The blue response of the devices have better fill-factors than the red response indicating defects at the interface. Further, I-V-T and C-V measurements also corroborate the presence of defect states which seem to prevent the spread of the depletion region in crystalline silicon. The photoresponse was found to be very sensitive to the interface defects and the fill-factors ranged from 0.42, for the sample in which the depletion region had spread, to 0.1 in those where the depletion region had been reduced in thickness by the interface states.

scholarly journals Conductivity and Photoconductivity of a p-type Organic Semiconductor under Ultra-Strong Coupling

2020 ◽  
Author(s):  
Kalaivanan Nagarajan ◽  
Jino George ◽  
Anoop Thomas ◽  
Eloïse Devaux ◽  
Thibault Chervy ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Organic Semiconductors ◽  
Linear Response ◽  
Carrier Transport ◽  
Spectral Response ◽  
Electromagnetic Environment ◽  
Strongly Coupled ◽  
Type Semiconductor ◽  
P Type ◽  
First Time

It has been shown that light-matter strong coupling of materials can lead to modified and often improved properties which has stimulated considerable interest. While charge transport can be enhanced in n-type organic semiconductors by coupling the electronic transition and thereby splitting the conduction band into polaritonic states, it is not clear whether the same process can also influence carrier transport in the valence band of p-type semiconductors. Here we demonstrate for the first time that it is indeed possible to enhance both the conductivity and photoconductivity of a p-type semiconductor rr-P3HT that is ultra-strongly coupled to plasmonic modes. It is due to the hybrid light-matter character of the virtual polaritonic excitations affecting the linear-response of the material. Furthermore, in addition to being enhanced, the photoconductivity of rr-P3HT shows modified spectral response due to the formation of the hybrid polaritonic states. This illustrates the potential of engineering the vacuum electromagnetic environment to improve the opto-electronic properties of organic materials.

Extension of Spectral Response of p‐Type Gallium Phosphide Electrodes by Metal Adatoms

1978 ◽  
Vol 125 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Hiroshi Yoneyama ◽  
Shuichi Mayumi ◽  
Hideo Tamura
Keyword(s):  
Gallium Phosphide ◽  
Spectral Response ◽  
P Type

scholarly journals Increased photocurrent in a tandem dye-sensitized solar cell by modifications in push–pull dye-design

2015 ◽  
Vol 51 (18) ◽  
pp. 3915-3918 ◽  
Author(s):  
C. J. Wood ◽  
G. H. Summers ◽  
E. A. Gibson
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Spectral Response ◽  
Dye Sensitized Solar Cells ◽  
Photocurrent Density ◽  
Dye Sensitized Solar Cell ◽  
Dye Sensitized ◽  
P Type ◽  
Sensitized Solar Cells

New donor–π–acceptor dyes functionalised with a bodipy or indolium acceptor are described, which have an excellent spectral response in the red region and generate record photocurrent in tandem dye-sensitized solar cells. Our cationic acceptor dye, CAD3, generated a cathodic photocurrent density of 8.2 mA cm−2, the highest reported for a NiO p-type solar cell to date.

Bandgap Shifting of an Ultra-Thin InGaAs/InP Quantum Well Infrared Photodetector via Rapid Thermal Annealing

1998 ◽  
Vol 525 ◽  
Author(s):  
D. K. Sengupta ◽  
S. Kim ◽  
H. C. Kuo ◽  
A. P. Curtis ◽  
K. C. Hsieh ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Spectral Response ◽  
Energy Levels ◽  
Blue Shift ◽  
Orbital Method ◽  
Quantum Well Infrared Photodetector ◽  
P Type ◽  
Anneal Time

ABSTRACTWe demonstrate that SiO2 cap rapid thermal annealing in ultra-thin p-type InGaAs/InP quantum wells can be used to produce large blue shifts of the band edge. A substantial bandgap blue shift, as much as 292.5 meV at 900°C has been measured and the value of the bandgap shift can be controlled by the anneal time. Theoretical modeling of the intermixing effect on the energy levels is performed based on the effective bond-orbital method, and we obtain a very good fit to the photoluminescence data. Compared to the as-grown detector, the peak spectral response of the annealed detector was shifted to longer wavelength without any major degradation in the responsivity characteristics.

Growth and Characterization of Interfaces in P-Type InGaAs/InP Quantum-Well Infrared Photodetectors with Ultra-Thin Quantum Wells

1996 ◽  
Vol 450 ◽  
Author(s):  
D. K. Sengupta ◽  
S. Kim ◽  
T. Horton ◽  
H. C. Kuo ◽  
S. Thomas ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Structural Parameters ◽  
Spectral Response ◽  
Interface Roughness ◽  
Scanning Tunneling ◽  
Infrared Photodetectors ◽  
Cross Sectional ◽  
Quantum Well Infrared Photodetectors ◽  
P Type

ABSTRACTP-type InGaAs/InP quantum-well infrared photodetectors operated at 4.55 μm require the growth of ultra-thin (10 Å) quantum wells. We report a study of interfaces in QWIPs grown by gas-source molecular beam epitaxy in which we optimized the group V source supply sequence so that a 6 K photoluminescence linewidth as narrow as 8.4 meV was observed from a structure with 10 Å wells. Analysis of the PL suggests that interface roughness was minimized. Cross-sectional scanning tunneling microscopy, double crystal x-ray diffraction, and cross-sectional tunneling electron microscopy confirmed that high-quality interfaces and uniform layers were obtained. Using the derived structural parameters, photocurrent spectral response was theoretically predicted for these QWIPs and then experimentally verified.

scholarly journals Conductivity and Photoconductivity of a p-type Organic Semiconductor under Ultra-Strong Coupling

2020 ◽  
Author(s):  
Kalaivanan Nagarajan ◽  
Jino George ◽  
Anoop Thomas ◽  
Eloïse Devaux ◽  
Thibault Chervy ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Organic Semiconductors ◽  
Linear Response ◽  
Carrier Transport ◽  
Spectral Response ◽  
Electromagnetic Environment ◽  
Strongly Coupled ◽  
Type Semiconductor ◽  
P Type ◽  
First Time

It has been shown that light-matter strong coupling of materials can lead to modified and often improved properties which has stimulated considerable interest. While charge transport can be enhanced in n-type organic semiconductors by coupling the electronic transition and thereby splitting the conduction band into polaritonic states, it is not clear whether the same process can also influence carrier transport in the valence band of p-type semiconductors. Here we demonstrate for the first time that it is indeed possible to enhance both the conductivity and photoconductivity of a p-type semiconductor rr-P3HT that is ultra-strongly coupled to plasmonic modes. It is due to the hybrid light-matter character of the virtual polaritonic excitations affecting the linear-response of the material. Furthermore, in addition to being enhanced, the photoconductivity of rr-P3HT shows modified spectral response due to the formation of the hybrid polaritonic states. This illustrates the potential of engineering the vacuum electromagnetic environment to improve the opto-electronic properties of organic materials.

scholarly journals Enhancement of Spectral Response inμc-Si1-xGex:H Thin-Film Solar Cells with a-Si:H/μc-Si:H P-Type Window Layers

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yen-Tang Huang ◽  
Cheng-Hang Hsu ◽  
Chuang-Chuang Tsai
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Conversion Efficiency ◽  
Spectral Response ◽  
Short Circuit ◽  
Thin Film Solar Cells ◽  
Window Layer ◽  
Microcrystalline Silicon ◽  
P Type ◽  
20 Nm

The hydrogenated amorphous silicon (a-Si:H)/hydrogenated microcrystalline silicon (μc-Si:H) double p-type window layer has been developed and applied for improving microcrystalline silicon-germanium p-i-n single-junction thin-film solar cells deposited on textured SnO2:F-coated glass substrates. The substrates of SnO2:F, SnO2:F/μc-Si:H(p), and SnO2:F/a-Si:H(p) were exposed to H2plasma to investigate the property change. Our results showed that capping a thin layer of a-Si:H(p) on SnO2:F can minimize the Sn reduction during the deposition process which had H2-containing plasma. Optical measurement has also revealed that a-Si:H(p) capped SnO2:F glass had a higher optical transmittance. When the 20 nmμc-Si:H(p) layer was replaced by a 3 nm a-Si:H(p)/17 nmμc-Si:H(p) double window layer in the cell, the conversion efficiency (η) and the short-circuit current density (JSC) were increased by 16.6% and 16.4%, respectively. Compared to the standard cell with the 20 nmμc-Si:H(p) window layer, an improved conversion efficiency of 6.19% can be obtained for the cell having a-Si:H(p)/μc-Si:H(p) window layer, withVOC = 490 mV,JSC = 19.50 mA/cm2, and FF = 64.83%.

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